Followed by the fact that basis of information communication is put by development of network technology, it has become possible to transmit, on the real time basis, data of moving picture through communication network. Under such infrastructure, utilization of the technology in which video camera is installed or provided at remote place to carry out remote control of that video camera through network to view desired moving pictures is being expected in the field of security, advertisement, information guide, real estate, remote medical service and the like.
As a video camera which permits such a remote control, there are utilized pan/tilt video cameras adapted to mechanically move view point of the video camera, so called pan or tilt it with a predetermined position being as reference to change position of image pick-up to carry out zooming to change angle of visual field.
Since this pan/tilt video cameras have mechanically movable portion, there are the problems that, as compared to video cameras only electronically operative, this pan/tilt video camera is inferior in reliability and periodical maintenance is required, and because it takes a predetermined time in operation, there exists time lag until a desired picture image is transmitted.
Moreover, the pan/tilt video cameras mechanically operative cannot provide image of view points or angles of visual field of image pick-up different from each other with respect to plural users.
Further, at pan/tilt video cameras used in the state installed or provided at remote place, in order to permit image pick-up, e.g., over a broad range of substantially 360 degrees, image pick-up lens using cone-shaped mirror is used. In the image pick-up lens using cone-shaped mirror of this kind, distortion takes place from a structural point of view. In view of the above, there are provided various technologies for eliminating distortion in picture image data when the cone-shaped mirror is used to carry out image pick-up.
In addition, there are also provided image pick-up systems in which distortion of picture image at the position where user desires of picture images imaged by using the image pick-up lens using cone-shaped mirror is removed to transmit such picture image to user existing at remote place so that user can obtain desired pan or tilt picture image even if camera does not pan or tilt.
The conventionally proposed technology for eliminating distortion of picture data only converts (transforms), by coordinate conversion (transformation), pixel positions of the portions having distortion at the periphery of picture image, and cannot provide sufficient resolution and the portion having distortion is inferior as compared to the portion having no distortion from a viewpoint of picture quality.